Chemical composition, physicochemical and functional properties of lupin (<i>Lupinus albus</i>) seeds grown in Ethiopia

Abstract

White lupin (Lupinus albus) seeds collected from the local markets of Debretabor (DT) and Dembecha (DB) in Ethiopia were studied for their chemical composition, physicochemical and functional properties. Moisture, total ash, crude protein, crude fat, crude fiber and minerals were determined. Mean values for protein, crude fat, total carbohydrates, crude fiber, and crude ash content of the two samples were 40.22, 8.92, 47.73, 10.08 and 3.15 g/100g, respectively on dry weight basis. The mean values of minerals such as phosphorus, iron, zinc and calcium contents for the samples were 248.90, 12.51, 4.68 and 82.56 mg/100g, respectively on dry weight basis. There was significant difference (p < 0.05) on physicochemical properties such as seed mass, seed volume, hull content, hydration coefficient, swelling capacity, cooking time, and seed hardness. However, the mean diameter, bulk density, sphericity, water absorption, swelling coefficient and swelling index were not significantly different between the two lupin seed samples. There was strong positive correlation between calcium content and the cooking time of lupin. The lower calcium concentration leads to a better cook ability and shorter cooking time. Hardness was negatively correlated with water absorption, and positively correlated with cooking time of the lupin seed. The flour obtained from Dembecha lupins was found to be superior to that of Debretabor in terms of the foaming capacity and bulk density. Lupin flour from Debretabor exhibited significantly higher dispersibility and water absorption than Dembecha, while the oil absorption was practically the same for the two lupins. Furthermore, a relationship exists between a water absorption capacity and the least gelation concentration. The results of chemical composition, physicochemical and functional properties for both lupin samples indicated that lupins can be used as a raw material for various food products manufacturing and provide consistency in food processing, analogous to other food legumes. Therefore, the research findings can be used by food companies in recipe development of lupin-based processed foods, including fortified food products to combat the protein-energy malnutrition (PEM) problem in Ethiopia and other East African countries.

Key words: Lupin, Chemical composition, Functional properties